AP Physics 2mediummcq1 pt
A wire has a resistance of 5Ω. If the wire is stretched to twice its original length while maintaining the same volume, what will be its new resistance?
A.A) 5 Ω
B.D) 40 Ω
C.C) 20 Ω
D.B) 10 Ω
Explanation
Core Concept
When the wire is stretched to twice its original length, its cross-sectional area decreases by half to maintain the same volume. Since resistance is proportional to length and inversely proportional to cross-sectional area, R = ρL/A, doubling the length and halving the area results in a resistance that is 2 × 2 = 4 times the original resistance. Therefore, the new resistance is 4 × 5Ω = 20Ω.
Correct Answer
CC) 20 Ω
Practice more AP Physics 2 questions with AI-powered explanations
Practice Unit 4: Electric Circuits Questions →